Propellant powder and process for making same



Patent ay 10, 127.

Amazon. s. ONEIL, or Essa." Amen, ILLINOIS, ASSIGNOB. T WESTERNCARTRIDGE 'coaaremr, or EAST ALTON, ILLINOIS,'A CORPORATION or DELAWARPEOPELLANT POWDER AND PROCESS FOR MAKING SAME.

- No Drawing.

This invention relates to propellant powders, and more particularly tonitro-cellu-- lose powders adapted for use in and suitable for cylinderguns and small arms.

Smokeless powder having a nitrocellulose base, adapted for rifle firearms and more particularly for use .as military ammunition,

The nitrocellulose is then dehydrated by displacing the water withalcohol in a. dehydrating press. The dehydrated product has then addedthereto ethyl-ether together with a stabilizer, such as diphenylamin,and the whole mixed or incorporated so as to form a colloid. Thiscolloid is then formed smoke, while both have a corrosive action intoblocks, pressed through dies to form strings and the strings :can be cutto form the grains. The grains'are then placed in a solvent recoveringapparatus to recover the solvent and are then dried. i

The above process forms a dense nitrocellulose colloid which burnsprogressively, that is, in layers until completely consumed. While itis, therefore, peculiarly adapted for rifle arms where the projectileseals the bore, it is not suitable for cylinder uns and small arms. Inpowders for cylinder guns, it is necessar that the initial burning be ata more rapit rate, due to the fact thatthe bore of the gun is not sealedby the projectile. Accordingly if the pressure is not rapidly developed,incomplete burning results, since the rapidity ofburning de endsdirectly upon pressure. According y, where a dense nitrocellulose powderis employed in a cylinder gun, the result will be unburnt powder andescape of the gases around the wads, thereby reducing the ballisticefliciency. I A

In the preparation of nitrocellulose powder for use as militaryammunition, it has Application filed February 10, 1923. Serial No.618,888@

further been the practice to ubject the dense nitrocellulose colloid tosurface treatment by coating or impregnating the same with a suitable.nitro-hydrocarbon, thereby producing'a so-called progressive powderhaving. a. still lower initial pressure without, however, lowering thevelocity of the projectile. The function of the solvent, however, is toact as a deterrent, as this solvent is'not only less explosive and lessreadily ignitable' than the dense nitrocellulose colloid, but it acts asa seal; it will, therefore, be seen that this surface treatment goesstill I further inthe opposite direction than the requirements andcharacteristics desiredin a-powder suitable'for use incylinder guns andsmall arms.

In order to produce a smokeless powder having a nitrocellulose base,ithas been the practice heretoforeto either mix with the;nitrocellulose, metallic nitrates or a more 'violent explosiveingredient, such as nitroglycerin. The. former, however, produces onthe'bore of the gun. It has also been the practice to employ weaksolvents so as to only partially gelatinize the nitrocellulose, or toemploy ingredients with thenitro-'- cellulose while in-a plastic statewhich are subsequently extracted. These, however, are open to theobjection that they do not provide stable and uniformly burning grainsIt has also been proposed to incorporate with smokeless powder, eitherby mixing therewith or as a supplementary priming charge,

black powder or to cause the black powder to adhere to thenitrocellulose powder grains by a binder. These, however, are not onlyopen to the objection that they introduce smoke forming and corrosiveconstituents,

but the black powder'is liable'to segregate during shipment, therebycausing 'a given charge to beununifornl.

' One of the objects of this invention, therefore, is to provide apropellant owder and more particularly one having a ense nitrocellulosecolloid as a base, together with a process of making the same, wherebythe surface of the powder grain is so modified that itwill approach therate of burning of the so-called bulk powders, and in order that thisrate of burnng may he so accelerated that the initial pressure isdeveloped at the rate required to enable its utilization and render itsuitable for cylinder guns and small arms.

There are at the present time large quantities of military ammunition,both surface treated and untreated, which have no present use. It isnoteconomical to keep such powder in storage, especially since itdeteriorates and it is entirely unsuitable for peace and economicpurposes.

Another object of this invention, therefore, is to provide a processadapted for the treatment of military smokeless powders so as to permittheir utilization in and render them suitable-for cylinder guns andsmall arms, and to so modify such military powder" that the rate ofburning is accelerated in order that the pressure may be developed morereadily. The process is not, however, restricted to the treatment ofdense military powders which have been salvaged, but it is adapted tothe treatment of freshly prepared dense nitrocellulose powders.

Further objects will appear from the detail description in which aregiven a number of examples illustrating embodiments of this invention.

In accordance with this invention. the powder grain is modified so as toform a dense core surrounded by a less dense and porous envelope. Thisis accomplished by swelling the .surface of the grain to the desireddepth of penetration and the swollen envelope so formed is then fixed.Thisfixing is accomplished in such a manner as to cause not onlyinterruption of the swelling in order to secure an envelope of thedesired depth, but also to break up the surface in order to leave anopen and porous envelope which is readily ignitable.

Generally stated which, upon penetration into the grain,

causes an envelope to be formed which is less dense than the body of thedense colloid,

and the solvent action is continued until the desired depth ofpenetration and the desired envelope thickness has been obtained. Theaction is then interrupted in such a manner as to not only limit thepenetration, but so as to also produce an envelope which is not. onlyless dense than the core which it suras a base material a densecolloided nitrocellulose powder, such as standard untreated the densenitrocellulosecolloidis subjected to the action of a solvent The powder1s ground or cut up in any suitable apparatus to the state of divisiondesired and it is then screened to the desired size. This powder is thenintimately mixed with a solid nitro-hydrocarbon, such asdinitro-toluene, in the proportion of ninetyeight (98)'parts of thepowder and two (2) parts of the solvent, although the-proportions maybe-varied within limits to suit requirements. The mixture is thenintroduced into a tank provided with a stirring mechanism, or into atumbling barrel, which .tank or barrel has been previously filled withwater and raised to a temperature of to 100 (1, depending upon thenature of the solvent used. The temperature is maintained (by supplyinglive steam or water to a jacket or by thedirect action of steam) for asuitable period, in case where dinitrotoleune is used for a period ofabout two hours, while the powder and the solid solvent arerumbledtogether in the water. The solvent under the influence of heatmelts and distributes itself uniformly .over the grain. Nowdinitro-toluene (as well as other solid nitro-hydrocarbon solvents)under the influence of heat is a solvent and a colloiding agent fornitrocellulose.

Accordingly the solvent penetrates the powder grain, the depth ofpenetration depending upon the period of heating, the quantity of thesolvent, andthe temperature of the heat applying vehicle. It isessential that the penetration takes place rather rapidly, otherwiselittle or no swelling of the grain takes'plaee. It is also essential"that the temperature be maintained until the desired penetration takesplace.

swelling action has progressed as far as de-' sired, cold water isadmitted to the mixture in order to rather suddenly chill the contentsof thetank or barrel. This causes the dinitro-toluene to chill, therebypartially recrystallizing and losing its solvent properties so that thesolvent action is interrupted. At

, the same time, a portion.of the nitrocellulose is partiallyprecipitated from. the colloid, while the dinitro-toluene is alsopartially precipltated. Accordingly the envelope,

which before the chilling consisted of nitrocellulose colloided withdinitro-toluene, will become partially decolloided. The chilling densecolloid core while the envelope is less I dense than the core andporous. The porous formation of the surface not only causes the powdergrain to ignite more readily but the particles of precipitatednitrocellulose are more readily ignitable than 'was the original densecolloid. The structure of the envelope is, therefore, such that it isnot only readily ignitable, but it will continue to burn at a higherrate under a reduced pressure, so that if the burning of the envelopesupplies the necessary temperature and pressure to afford completecombustion of the balance of the grain. This rate of combustion canberegulated by variation ofthe thickness of the envelope, which canreadily be controlled by extending the penetration period of thesolvent.

It will, of course, be understood that after chilling the treated grainsare removed from the water and dried in the usual manner.v

This drying will not, however, cause contraction of the envelope to theoriginal-colloid density, but this envelo willremain in a porouscondition since t e drying will rather. enhance than detract from theporosity. The drying can be accomplished in any suitable manner asusualin the art.

If a coatedpowder is desired, additional dinitro-toluene may be addedafter chilling, the water reheated until the solvent is melted anddistributed over the surface and chilling P again proceeded with. v

While in the above described embodiment of the process dinitro-toluenehas been described as a solvent, it is understood that other solidsolvents may be used, such as dinitro-benzene, nitro-naphthalene orothersolid ntro-hydrocarbons. The procedure when using such solvents issimilar to that described above. V

It is also ossible to obtain improved results by emp oying dilutedvolatile solvents, such as acetone, ketones, wood alcohol, etc.

When using volatile solvents, however, the

dense powder is subjected to the actionpf the volatile solvents, eitherin waterprin the presence of another liquid which Is indiffercut tonitro-cellulose. The action ofthis solvent causes the grains to swelland; in-

crease in volume, and the treatment is continued until the desiredpenetration has been effected. The treated grains are then quicklyimmersed in hot water which causes violent expulsion of the solvent;thegrams so treated may then be chilled by dropping is not necessarilylimited thereto.

them in cold water. The grains may then be dried 'in any suitablemanner.

' It will thus be seen that the invention accomplishes its objects. Apowder is obtained which comprises a core of a dense nitrocellulosecolloid which is enveloped by a less dense and porous envelope, whichenvelope being further decolloided, and arts of the broken and poroussurface containing uncolloided nitrocellulose which is readilyignitable, and an uncolloided combustible solvent. The result,therefore, is a powder grain whose surface is readily ignitable, so thatits combustion is not only started at low pressure, but the envelopesupplies and so maintains the necessary heat and pressure to secure andmaintain the requirements for complete combustion of the dense core.

'Moreover the character and formation of grains. It will further benoted that the desired result is obtained without the mixture of smokeformin or corroding. ingredients, since the'resulta 1'. grain is itselfmodified by modifying the density, porosity and chariictgr of thesurface of the nitrocellulose col- While in the specification and claimsthe term grain is used, it is to be understood that it is intended as aWord of eneral description and not of limitation, ut to include thevarious forms in which powder is roduced for use. It will be furtherunderstood that while theories of formation and operation have beenadvanced, the invention It will further be obvious that various changesmaybe made in details without departing from the spirit of thisinvention; it is, therefore, to be understood that this invention is notto be limited to the specific details described.

Having thus described the invention, what is claimed is:

. 1. A propellant powder grain comprising, a dense core surrounded by aporous envelope.

2. A propellant powder grain comprising, a dense colloid, the surface ofwhich is porous.

3. A propellant powder grain comprising, a dense colloid, the surface ofwhich is partially decolloided.

4. A propellant powder grain comprising, a dense colloid, the surface ofwhich is colloided. with a solvent so as to provide an envelope which isless dense than the core.

5. A propellant powder grain comprising,

Int)

a dense colloid, the surface of which is colloided with a solvent so asto provide a porous envelo e.

6. A propell a dense colloid, the surface of .which is partiallydecolloided and contains a combustiwith a solvent and is less densethan'thecore.

12. A powder gram of dense colloided nitrocellulose, the surface ofwhich is porous so as to be readily ignitable.

13. A powder grain of dense colloided nitrocellulose, the surface ofwhich is colloided with a solvent and chilled. v

14. A powder grain of dense colloided nitrocellulose having a chilledcolloided surface.

15. A powder grain 'of dense colloided nitrocellulose, the surface ofwhich contains a precipitated nitro-hydrocarbon.-

16. A powder grain of dense colloided nitrocellulose, the surface ofwhich contains precipitated nitrocellulose.

I 17. A powder grain of dense colloided nitrocellulose, the surface ofwhich contains precipitated nitrocellulose and a nitro-hydrocarbonsolvent.

. 18. In the art of making propellant powder, the rocess comprising,swelling the surface of t e grain and fixing the envelope so formed.

19. In the art of making propellant powder, the process comprising,swelling the surface. of the grain and chilling the envelope so formed.y

20. In the art of making propellant powder, the process comprising,subjecting the grain to the action of a solvent for the grain materialand -precipitating the solvent.

21. In -the-art of'making propellant powder, the process comprising,subjecting the surface of the grain to the action of a solvent for thegrain material and expelling the solvent.

22. In the art of making propellant powder, the process comprising,heating a grain, the surface of which contains a solvent and chillingthe grain.

23. In the art of making propellant powder, the process comprising,swelling the surant powder grain comprising,

face of a dense nitrocellulose colloid and fixing the envelope soformed.

24. Inthe art of making propellant powder, the process comprising,swelling the surface of a dense nitrocellulose colloid .and' chilling.the envelope so formed. r 25. In. the art of making propellant powder,the rocess comprising, partially decolloiding tlie surface of a densenitrocellulose colloid.

26. In the art of making propellant powder, the process comprising,subjecting a dense nitrocellulose colloid to the action of a swellingmedium and interrupting the swelling so as to fix the envelope soformed.

27. In the art of making'propellant powder, the process comprising,subjecting a dense nitrocellulose colloid to the action of a solvent andinterrupting the solvent action so as to fix the envelope so formed.

28. In the art of making propellant powder, the process comprising,subjecting a dense nitrocellulose colloid to the action of a swellingmedium and expelling the medium from the envelope so formed.

29. In the art of making propellant powder, the process comprising,treatin a dense nitrocellulose colloid with a solvent or nitrocelluloseand precipitating the solvent.

30. In the art of making propellant powder, the process comprising,colloiding the surface of a dense nitrocellulose colloid with a solventfor nitro-cellulose and fixing the envelope so formed.

31. ,In the art of making propellant powder, the process comprising,colloiding the surface of a dense nitrocellulosecolloid with a solventand partially decolloiding the envelope so formed.

32. In the art of making propellant powder, the process com rising,heating a dense nitrocellulose colloi in the presence of a solvent andchilling the envelope so formed.

33. In the art ofmaking propellant powder, the process comprising,heating a dense nitrocellulose colloid in the presence of anitro-hydrocarbon solvent and chilling the envelope so formed.

34. In the art of making propellant powder, the process comprising,heating a dense nitrocellulose colloid in the presence of a solvent anda vehicle and chilling the enve lope so formed.

35. In the art of making propellant powder, the process comprising,heating a dense nitrocellulose colloid in the presence of anitro-hydrocarbon in water and chilling the envelope so formed.

36. In the art of making propellant powder, the process comprising,treating a dense nitrocellulose colloid with a nitro-hydrocarbon firstin hot water and then in cold water.

37. In the art ofmaking propellant powder, the process comprising,treating a dense nitrocellulose colloid with a solid nitrohydrocarbonfirst in hot water and then in der, the process comprising, rumbling adense cold water. nitrocellulose colloid with a solid solvent in 38. Inthe art of making propellant powhot water and then'treating theresulting l0 der, theprocess comprising, rumbling a dense colloid withcold water. 5 nitrocellulose colloid 'with a solid solvent in Intestimony whereof I affix my signature hot water. this 31st day of January, 1923.

39. In the art of making propellant pow- ARTHUR S. ONEIL'

